dis cussed more fully in the Trig gered Meas ure ments
sec tion below.
Range Hold may be se lected (see page 4-6 ) to limit dy -
namic range and pre vent small range change dis tur -
bances on very high speed sig nals. Use Range Hold 1 for
meas ure ments down to –25 dBm, and Range Hold 2 up
to –25. If the dis play up date is turned off via GPIB, only
the av er age is up dated.
Trig gered
Meas ure ments
Since non- triggered meas ure ments are of lim ited use in the PROFILE mode,
most ap pli ca tions re quire trig ger ing. For ex am ple:
1. Pro vide a 1 kHz square wave modu lated sig nal to sen sor A, and set
TRIGGER|SETUP|MODE to In ter nal A (Int A). This causes the PROFILE
sweep to wait un til a cer tain power level is pres ent on the sen sor be fore start -
ing the sweep.
2. The DELAY and WIDTH pa ram e ters, as dis cussed above, are the po si tions
of the two CURSORS. These can be set to spe cific lo ca tions; for ex am ple, if the
sig nal is a 1 kHz square wave, set ting the DELAY to 250
ms places the cur sor
in the first cy cle at the mid point of one of the phases. Set ting the WIDTH to
500
ms sets the other CURSOR to ex actly one half-cycle later, thus al low ing dis -
play of the power lev els in the two phases of the sig nal.
NOTE
If the modu la tion is turned off, then the trig ger con di -
tions will not be met and the sweep will not con tinue to
be up dated. This is use ful to ‘freeze’ a dis play. To dis -
play a CW sig nal again, re- select CON TINU OUS trig ger
in TRIG GER|SETUP|MODE.
In some con di tions, it is use ful to view trig gered sig nals
in de pend ent of sig nal lev els. In these cases, pro vide an
ex ter nal trig ger source into the rear panel TRIG GER
in put to trig ger such a meas ure ment.
3. The dy namic range in PROFILE mode should ex tend to the maxi mum speci -
fi ca tion of the me ter, to ap proxi mately –40 dBm (di ode sen sors only). If the dis -
played range is re stricted, check that RANGE HOLD is not ap plied.
NOTE
If RANGE HOLD 1 is ap plied, the lower limit will be
ap prox i mately –30 dBm. If RANGE HOLD 2 is ap plied,
the max i mum level will be lim ited to ap prox i mately –10
dBm. In most trig gered sit u a tions, range hold should be
set to AUTO.
ML2400A OM 5-13
PROCEDURES PROFILE OPERATION MODE
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